onsemi (Ansemi)

SOIC-8

Tube

98

UC3844B, UC3845B series are high performance fixed frequency current mode controllers. These devices are specifically designed for off-line and DC-DC converter applications, providing designers with a cost-effective solution with minimal external components. These ICs feature an oscillator, temperature compensated reference, high gain error amplifier, current sense comparator, and high current totem pole output suitable for driving power MOSFETs. Also included are protection features with input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limit, latch for single-pulse metering, and flip-flops for interval shutdown of the output every other oscillator cycle, Output dead time can be programmed from 50% to 70%. These devices are available in 8-pin dual inline plug-in and surface mount (SO-8) plastic encapsulation and 14-pin plastic surface mount (SO-14) encapsulation. The SO-14 encapsulation has separate power and ground pins for the totem pole output stage. The UCX844B has UVLO thresholds of 16 V (on) and 10 V (off), suitable for offline converters. The UCX845B is suitable for low-voltage applications with UVLO thresholds of 8.5 V (on) and 7.6 V (off).